Intrinsic positive end-expiratory pressure (intrinsic PEEP or PEEPi) is a phenomena occurring due to insufficient expiratory time, preventing the lungs of a patient from becoming sufficiently emptied at the end of expiration, trapping air in the lungs, and increasing the end-expiratory lung volume (dynamic hyperinflation).
During mechanical ventilation of a patient, the presence of dynamic hyperinflation and intrinsic PEEP (PEEPi) can be aggravated by high levels of mechanical ventilation and trigger/off-cycling settings on the mechanical ventilator.
Clinical methods to detect/quantify intrinsic PEEP (PEEPi) comprise measuring pressures at an opening of mechanically ventilating airways during occlusions of those airways; such methods are difficult to interpret during spontaneous breathing.